I assist teaching homeopathy classes so I have contacts with lots of moms ISO chicken pox. I've given vaccine talks in Mt. Pleasant, Newago, Rockford, Greenville, Lansing, and Durand so I might get leads that require a little travel.
My oldest child got chicken pox inadvertently from the church nursery when he was 19mo. He only had two pox and my then 6mo solely BFing daughter didn't get them. As I've pursued chicken pox actively for the past seven years, it's been my observation, contrary to the statements by the CDC and other HCPs, that chicken pox is MOST contagious before the pox break out and *very* difficult to spread between break out and crusting over. IME the only successful transfers happened before the pox parties and broke out after.
That being said I'm subbing, will pass on leads, and will *definitely* let everyone know if my children haven't broken out but were exposed to children who later did.
P.S. I normally think of CP as a spring thing (sometimes late winter as a PP stated) but it's the fall CP that has by far the highest rate of vaccine strain CP. I've seen too many funky and entrenched (up to 3 mos) cases to intentionally expose my children to the vaccine strain.